Only pulverization methods have been conventionally used for producing toner for use in developing an electrostatic image in electrophotographic image forming apparatus such as copiers, printers, facsimiles and multi-functional products having two or more of copying, printing and facsimileing functions. However, recently polymerization methods in which toner particles are formed in an aqueous medium are used more broadly than pulverization methods. The toner produced by a polymerization method is called a polymerized toner or a chemical toner.
The derivation of the name “polymerized toner” is that when toner particles are prepared, a polymerization reaction of toner raw materials is performed. Recently, various polymerization methods are practically used, and specific examples thereof include suspension polymerization methods, emulsion polymerization methods, polymer suspension methods (polymer aggregation methods), and ester elongation reaction methods.
Since polymerization methods have advantages over pulverization methods such that relatively small toner particles can be produced; the particle diameter distribution is relatively narrow; and high quality images can be produced when polymerized toner is used for electrophotography because the particle shape is close to sphere. However, all toner particles are produced at the same time, it is hard to prepare toner particles having a sharper particle diameter distribution (such as toner particles having substantially the same particle diameter).
In attempting to produce toner particles having a sharper particle diameter distribution, JP-2006-293320-A discloses a toner production method using a liquid ejection/granulation method.
The present inventors recognize that a need exists for a toner production method by which toner particles having a sharper particle diameter distribution can be produced in a relatively short time (i.e., at low costs) with hardly forming united and aggregated particles using an apparatus with a small drying area.